Figure 1.

Cryopreservation of embryogenic cultures of holm oak by the vitrification-based method. a–c Show individual nodular embryogenic structures (a), groups of globular-heart stage embryos (b) and early cotyledonary stage embryos (c) isolated from line Q8. (d) Somatic embryos developed from a cryopreserved nodular embryogenic structure after 3 weeks of culture on proliferation medium. (e) Somatic embryo recovery from nodular embryogenic structures of line Q8 cryopreserved in liquid nitrogen for 4 years and cultured on proliferation medium for 8 weeks. Diameter of Petri dish, 90 mm.